Traction device for automotive vehicles



Jan. 3l, 1950 F. cEsEN 2,496,119

TRACTION DEVICE EUR AUTOMOTIVE VEHICLES Fil-ed Maron 7, 194e 4Sheets-Sheet 1 Jan. 3l, 1950 F. cEsi-:N

TRAOTION DEVICE FOR AUTOMOTIVE VEHICLES 4 Sheets-Sheet 2 Filed March 7,1946 /NVE/VTOR Fran/f C65@ O B7 /1/7 i WJ Jan 31, 1950 F, QESEN2,496,119

TRACTION DEVICE FOR AUTOMOTIVE VEHICLES HTTOA/E Y Jan, 31, i950 F.cEsl-:N 2,496,119

TRACTION DEVICE FOR AUTOMOTIVE VEHICLES Filed March 7, 1946 4Sheets-Sheet 4 Patented Jan. 3l, 1950 OFFICE TRACTION DEVICE FORAUTOMOTIVE n VEHICLES Frank Cesen, Cleveland, Ohio Application March 7,1946, Serial No. 652618 (Cl. 23S-44) 12 Claims. l

This invention relates to devices for providing traction for the wheelsof automotive vehicles, when stalled because of ice, snow. mud, etc. onthe roadway.

Because of the differential gearing commonly provided between the engineand the two drive wheels of an automotive vehicle, if either Wheel restsupon a slippery roadway, it may be caused to slip and rotate and preventpropulsion of the vehicle by the other wheel; or if the vehicle isblocked by deep snow or mud the traction required of the driving wheelsmay be greater than can be developed on the slippery roadway and one orthe other of the-drive wheels will slip. In either event the vehiclewill be stalled unless the traction is articially increased.

Various devices have been proposed to provide such artiiicial traction;and amongV these are devices comprising a short piece of trackway whichcan be carried inr the vehicle and when needed may be laid on theroadway in front of the wheel and upon and over which the wheel mayroll; and the present invention relates to devices of this type.

Such devices as heretofore proposed have a number of defects which haverendered them iinpracticable and unsatisfactory.

Among these defects of prior devices are:

vThat the rounded. periphery of the rubber tire ofthe wheel which` mustengage and grip and ride up on the device, has Contact withthe device ononly a small point or zone on the tire, insuiiicient in contact area todevelop enough driving traction to start movement of the vehicle unlessthe tire is iirst jacked yup high enough from the roadway to permitputting the device under the tire That lugs or the like provided onprior devices in the attempt to insure traction between the tire and thedevice likewise do not afford suihcient traction-developing grip withthe tire;

That lugs or the likeI of prior devices as referred to have beendesigned so that if they give continuous traction they must be so closetogether, successively, as the tire rolls over them, as to becomeclogged or illled-over with snow, ice, mud, etc., and so as to renderthem ineffective unless cleaned out by hand.

That prior devices oi this type have had to be of. short length to beconveniently stored and carried in the vehicle and often this is notenough to enable the wheels to roll clear of' the diiliculty and outonto the solid traction developing part ofthe roadway.v

It isr among the objects of this invention vto provide generallyadeviceoi' this type in which these and other objections to priordevices are overcome.

Other objects are:

To provide a device of this class of unit length, long enough forordinary occasions, but which may be quickly and conveniently coupled toother like units to provide a continuous trackway of greater length;

To provide a device of the class referred to having roadway grippinglugs or teeth on its underside to prevent slipping of the device out ofposition in the use described; and which device when laid upside downpresents a iiat surface as a base for a vehicle jack; and the said roadgripping lugs constitute a fence like retainer to prevent the jack basefrom slipping off of the device.

Other objects will be apparent to those skilled in the art to which theinvention appertains.

The invention is fully disclosed in the following description taken inconnection with the accom# panying drawing, in which:

Fig. 1 is a top plan view of a device embodying the invention made in asingle piece as a metal casting; 1

Fig. 2 is a longitudinal sectional view from the plane 2 2 ofFig.. 1;

Fig. 3 is an end view from' the direction of the arrow 3 of Fig. 1;

Fig. 4 is a sectional view from the plane 4 4 of Fig. 2;

Fig. 5 is a bottom plan view of the device of Fig. l;

Fig. 6 is a top plan view of a plurality of devices similar to that ofFig-1 but modified to adapt them to be coupled together into acontinuous trackway as shown;

Fig. 7 is a longitudinal sectional view from the plane 'l-l of Fig. 6;

Fig. 8 is a fragmentary elevational View taken in the direction of. thearrow 8 of Fig. 6;

Fig. 9 is a top plan view of another form of the device similar to thatof Fig. 1 but as made from sheet metal;

Fig. 10.is a longitudinal sectional view taken from the plane i il-I 0of Fig. 9; f

Figs. il, 12,. and 13 aresectional views taken from the planes II-H,I2-I2, and 3-I3 re` spectively oi Fig. 9;.

Figs. 14', 15, and 16 are views similar to Figs. 11, i2, and ll?lrespectively, but illustrating a modication.;

Fig. 17 is atop 'plan view'oi a plurality of devices similar to that ofFig. 9 but modified to adapt them to be coupled together into a continuous trackway as shown;

Fig. 2l is a top plan view showing in solid line,`

another embodiment of the invention;

Fig. 22 is a sectional view from the plane 22-22 of Fig. 21;

Fig. 23 is a broken sectional view from the plane 23-23 of Fig. 21; and

Figs. 2l and 22 show in brokenlline how a number of the embodiments ofFigs. 21 and 22 may be coupled together longitudinally.

Referring to the drawing. and to the device.

embodying the invention as in Figs."l to 5 inclusive as made in a singlepiece from cast metal,

there is shown at I a dat base or elongated bottom, generallyrectangular in plan, having side walls 2 and 3 extending upwardlytherefrom. As is apparent, the bottom I at its 4opposite ends terminatesin edges 4 and 5, and these end edges are cut back or recessed toprovide concave arcuate end edge portions 6 and 1 preferably of circularcontour; and at .theupper side of these arcuate recesses 9 and 1 themetal is formed to provide relatively sharp or angular corner edges 8and 9.

- A plurality such asfive ns or fln walls, I0 to I4 inclusive, are castintegral with the bottom I, extend upwardlytherefrom and transverselythereof and join integrally with the side walls 2 and 3. -The lupperedges of Vthese fins are upwardly concave as indicated in Figs. 3 and 4,and are preferably vof circular contour, and these arcuate upper `edgesare serrated as shown at I5 to I8 for the fins I0,- II, I3, and I4.Preferably all of the nsln to I4 inclusive have the said upwardlyconcave serratededges but inasmuch as the serrated edges may in somecases if desired be omitted from the central fin I2, they have not beenshown in the drawing on that n.

The arcuate upper edges of the said fins,

whether serrated or not are formed so that the arcuate edge hasrelatively sharpor square corner edges I9 to 23 inclusive fortherespective iins.

The said fins .I0 to I4 are of different heights, this difference beingprovided preferably by utilizing different radii` for the respectivearcuate upper edges. As shown in Fig.' 2 and indicated in Fig. 3 the endtins I0 and I4 are the lowest, the fins II and I3 are higher than thefins I9 and I4 and the middle 'n I2 is the highest of them all, for apurpose to be described.

On the underside of the bottom I it has a relatively flat or planarsurface 24 and has cast integral therewith'sharp edged projections forgripping the roadway and Vinasmuch as they funetionas calks theyv willbe referred to as such. There is a transverse calk 25 near one end ofthe device having a downwardlysha'rp edge 25; and a similar transversecalk 21 'having a similar across the device as shown in Fig. 1 andindicated 4 twoflongitudinally extending 65 the wheel.' sharp edge 28,these calks extending transversely 4 calks 29 and 30 disposed adjacentto the side edges of the base extending downwardly therefrom and havingsharp downward edges 3I and 32, see Fig. 4.

As shown in Fig. 5, these four calks 25, 21, 29, and 39 constitute whatmay be referred to as a fence on the bottom of the device enclosingtherewithin a flat surface space 33 for a purpose to be referredv to. r'f In the Operation of the device of Figs. 1 to 5, reference may be madeto Figs. 19 and 20. In Fig. 19 an automobile wheel 34 having a rubbertire 35 rests upon a slippery but otherwise unobstructed roadway surface36. The device as described above is presented to the tire 35 by theoperator and in doing so he slides the calk edge 26 along the ground androcks the device counterclockwise as viewed in the figure until the saidsharp corner edges 8 and I9 engage the tire.

These edges because of their concave form embrace the rounded tire 35and engage it on a considerable angular extent therearound. The devicemay be forced inwardly so as to make the contact engagement of the tirewith the concave edges 8 and I9 a -gripping engagement.

Either end of the device may thus beV presented to the tire optionally;the corner edges 9 and 23 functioning the same asA the-said corner edges8 and I9. v l 1j When torque is'xapplied to the wheel in the clockwise`.direction of Fig. 19, the.`gripplng engagement therewith ofthefconcave sharp corner edge 8 and` the concave serrated sharp corneredge I9 develops accordingly great traction. and

the wheel rolls up onsthe rst fin III. .The gripping engagement with thefirst fin III is maintained by the serrationsthereon and by the concavecontour of the n'embracing the tire. The tire will therefore by tractionroll successively over this n and in a similar manner will engage thesharp corner :edges and concave serrated e'dges'of the other fins. `androll toward the rear end of the device and ultimately'will roll of! ofits other end and proceed over the roadway.

When the vehicle is stalled by a wheel in deep snow or mud asreferred'fto, the device may be presented to the wheeias` s'how'n inFig. 20. The snow or lmud may be sooped'out to provide an inclination 31upon which the device may be placed, and the device ispushed downwardlytoward the tire until the sharp serrated corner edge I9 on the fin I0eg'a'ges'the tire, and preferably also until the concave'serrted corneredge 2n on the second fin'lI engages v`the tire. Both fins embracetherounded setiori'of'the tire as referred to. 'I'he traction'thusdeveloped will cause the wheel to roll successively over `the ns as itclimbs up the inclination 'over the device.

In both the modes of operation of Figs. 19 and 20 the calks 25'and 21prevent slipping of the device while traction is beingdeveloped thereonand theside calks `29* and 39jg`ri`p and prevent lateral shifungpfthedvie'dut of the path of It has been found tliatjwlien` a successionof fins such as those shown from III to I4 inclusive are provided to besuccessively engaged by the tire, they should "be close enough togetherso that when the tirerolls overthe one finit may early in its movementengagej the `next successive iin to insure continued traction. Thisindicates that such fins should be placed Vclose together. But it hasbeen found thatif they are placed too close 5 together then snow` or.mud. .particularly^as in the case of Fig; 20, may fall into the deviceand iill up the spaces between the adjacent fins and render themineiective for gripping engagement with the tire. This can be avoided byspacing the ns farther apart; but then they are not close enoughtogether to insure continuous traction in going from one to the other.In the present device, this diiculty has been overcome by making themsuccessively higher toward the middle of the device, so thatnotwithstanding that they are disposed relatively far apart, to preventexcessive snow and mud collection as referred to the tire upon rollingover one nn makes early engagement with the next one at least until thetire has rolled to the longitudinal middle of the device, after whichthe momentum gained by the vehicle will reduce the need for artificialtraction.

It is contemplated in the practice of the invention that at least twosuch devices will be stored and carried in the vehicle, because if oneslipping wheel is given artificial traction by the device, the otherwheel may begin to slip and should likewise be given artificialtraction.

Since the driver of the vehicle will have at least one such device inhis vehicle at all times, and I have taken advantage of this fact toprovide an additional use for the device, namely as a base for a jack toraise the vehiclefor ordinary purposes such as changing a wheel or tire.

In this use of the device, it is turned upside down as indicated in Fig.5 and laid upon the ground; and the jack base is placed upon the iiatbottom surface 33, particularly when the ground is soft and the basemight sink into the ground, or when the ground is slippery or uneven andthe base of the jack might slip laterally. When the base of the jack isplaced on the surface 33, the calks surrounding this space in the natureofa fence as referred to, prevents slipping of the jack base on thedevice even if the device cannot be horizontally placed with the saidsurface horizontal. In many instances, when a driver attempts to use ajack as referred to, he must hunt around for a at stone or board to putunder the jack base, and such inconvenience is obviated by the use oftheabove described device as a jack base support.

In some cases, a single unit length of the device, such as that shown inFigs. 1 to 5 may not be sufficient. It may be necessary to provideartiiicial traction for the vehicle wheel over a greater distance beforethe wheel will come into contact with a roadway surface on which it willno longer slip.

In Figs. 6, 7, and 8, is 'illustrated a modification of the device ofFigs. 1 to 5 by which a number of said devices may be coupled togetherto provide a continuous trackway either on level slippery ground or uponan inclined snow or mud bank.

Referring to Figs. 6 to 8, there is shown at 38 and 39 and indicated at40 three such units having all of the operating features of the singleunit above described although the said serrations on the transverse inshave been omitted for the sake of simplification of the drawing, andhaving the following additional features. At their forward ends, theside walls 2 and 3 are bent inwardly as at 4I and 42 so that the forwardends `4| and 42 of one unit may be placed inside of the side walls 2 and3 at the rear end of another unit. A pair of lugs 43 and 44 are formedintegral with the side walls 2 and 3 respectively and with the bottom I,and theend portions 4I and 42 are s 6 provided on'the'irundersides withthe recesses 45 and 45 providing in effect hooks 4l and 48 which may behooked over the projections 43 and 44' to couple the forward hooked endof one unit with the rearward end of another unit.

Several units interlinked in this manner may be laid'along in alignmenton level ground or may extend upwardly over an inclination as indicatedin Fig. 7. As shown in Fig. 7 also, the recesses 45 and 4S are largerthan the projections 43 and 44, and as shown in Fig. 6 the hook ends 47and 48 are narrower in the overall dimension than the distance betweenthe walls 2 and 3, so that the succession of units may be laid either ina straight line asin Fig. 6, or each unit may be disposed at an angle tothe preceding unit, whereby the trackway mayl'follow a curve. It is notdeemed necessary to illustrate this in the drawing. Y

Referring to the form of the invention in Figs. 9 to 13 inclusive, itwill be seen that the essential features are the same as those of thefirst described form. The principal dillerenc'e is that the device hereshown can be fabricated Afrom sheet metal, The base 49 and side walls 55and Si are rst formed integrally by cutting and bending or press formingoperationsfinto a' trough-like body. To providthe transverse iins.,which in this case are shown at I52 to 56 inclusive, sheet metal piecesare formed and welded at their ends as indicated -at 51-to the'innerwall of the sides 59 and 5l: To'providethe upwardly concave edges onthe'ns the' pieces 52 to 56 .may rst be formed from straight barstock-.or

cut from sheet metal and then bentinto thec'onguration plainly shown inFigs; 1"1 to '13." "I'o cause the concave gripping edges oi the-ii'ns tobe successively higher'proceeding from the endof the device toward itsmiddle-the stock from which the ns .aiemade maybe successively'wider'asshown in going fromvFig'. 11 to Fig. 1'3. 'A f-' The 'iins 52 to 55 have'been shown without serrated edges as indicating that they iriall casesare not essential; but a corresponding tire'- gripping effect isprovided bythe shape'of the transverse fins. For example in Fig. 11, thefin 52 is shown as having an intermediate horizontal upper edge portion58; and at each side thereof inclined portions 59-'59. The tire beingresilient, will, as it rolls up on the fin 52 yield and engage all threeedge portions 58 and 59-59 and thus grip the iin. These edge portionsbeing of dif# ferent inclination tend to bite into the resilient tiremore effectively than if these edges were all disposed ona continuoussmooth concave arc, and therefore the different inclinations of theseedge portions function to produce generally the same effect asserrations.

When actual serrations are desired in this sheet metal form, they may beprovided on the upper edges of the iins of Figs. 11, 12; and 13; but inFigs. i4, 15, and 16, I have shown another way to provide them as amodification. Here the ns are indicated at 59, El, and 62 as welded attheir ends to the side walls 59 and 5! and suspended thereby; and the nsare formed from rectangular or square section bar stock twisted so thatthe edges of the twisted stock as at 63-63 provide teeth or serrationson the upper sides of the fins. The bars B3, 6|, and 62 beforebeingwelded, are bent to be concave on their serrated upper sides as shown inthe drawing, and each, lproceeding from the end of the device is weldedon at a higher elevation than the one preceding it to cause the ns to besuccessively higher as referred to.

To provide the aforesaid calks on the underside of the device, pieces ofangle section steel 64 and 65 are welded to the underside of the base49.

The mode of operation of this form will in its essential respects be thesame as that of the first described form.

In Figs. 17 and 18 is shown, to smaller scale, a modification of thesheet metal form of Figs. 9 to 13, by which a number of units may becoupled together to provide an elongated trackway.

The units in this form, three of which are shown at 6B, 61, and 68 madelike the units of Figs. 9 to 13 have the following diierences.

The side walls, of each unit, for example the side walls 69 and 10 ofthe unit 61 instead of being parallel, as in Fig. 9, are inclined o rtapered toward each other so that the forward end of the unit is, in itsoverall dimension, narrower than its rearward end, whereby the forwardend of one unit may be inserted into the rearward end of the unit aheadof it.

At the rearward end of each unit, a pair of posts 1l and 12 are weldedto the base of the unit at points adjacent the side walls thereof, andproject upwardly therefrom. At the forward end of each unit a pair ofperforations 13 and 14 are provided in the base of the unit.

, To couple a number of units together, into the relation shown in Figs.17 and 18, the forward end of one unit is inserted between the sidewalls of the next unit and the perforations 13 and 14 are telescopeddownwardly over the posts 1l and 12 respectively.

The transverse fins of these units may be like those of Figs. 11 to 13or of those of Figs. 14 to 16 as may be desired, and as will beunderstood, the type of fins shown in Figs. 11 to 13 being illustratedin Figs. 17 and 18.

The mode of operation of this kind of coupled unit is the sameas thatdescribed for the coupled units of Figs. 6 and 7.

In Figs. 21 to 23 is illustrated another embodiment of the invention, ingeneral similar to that of Figs. 6, 7, and 8, inasmuch as the device ismade from cast metal; and a brief description thereof will suffice.

A fiat base or bottom 15 has side walls 16 and 11 between which are ns18 to 82; the fins be- 82, being the lowest, the iin 80 at the middlebeing the highest, and the fins 19 and 8| being of an intermediateheight.

The upper edges of these fins are concave as shown in Fig. 23; and theend fins 18 and 82as shown for the 1in 18 in Fig. 23, and indicated inthe other figures, is serrated to increase the grip of the vehicle wheeltire therewith as referred to hereinbefore.

The upper edges of the side walls 16 and 11 are serrated havingconcavities as at 83-83 between pairs of fins; whereby, as will beapparent, when one of the devices is turned upside down and laid uponanother like device, for packaging or transportation, they will to aconsiderable degree nest with each other and occupy less space.

The base 15 extends at its opposite ends beyond the end fins 1B and 82;and as at 84 and 85; and has concave edges 86 and 81 for the tireengaging purposes described hereinbefore.

Longitudinal calks 88 and 89 and transverse calks 90 and 9| are providedsimilar to those described for Figs. 1 and 2, and for a like purpose,and the transverse calks 90 and 9| may each be in two longitudinallyseparate parts 90-90 and ing of different heights, those at the end, 18and ill-9|; and between the two parts, the base is provided withelongated perforations 92 and 93 functioning as hand holes by which thedevice may conveniently be picked up.

Except for the detail features mentioned above this form of the deviceand its functions are substantially the same as those of the device ofFigs. 1 and 2, or that of Figs. 6 to 8, but a different means isprovided to couple one to another endwise for the purposes referred tohereinbefore.

To this end, at one end of each device, for example the left end'of thedevice as viewed in Figs. 21 vand 22, laterally outwardly open hookdevices 94 and 95 are provided, L-shape as viewed from above andcomprising each a side wall 96 generally parallel to the side walls 19and 'l1 of the device, offset inwardly laterally therefrom; and integralwith the end iin 18 and with the portion 84 of the base extending beyondthe end fin, and having outwardly laterally extending hook portions91-91.

At the other end of the device hook devices 98-98 are provided, alsoL-shape in plan, and having hook side walls 99-99 formed by extensionsof the side walls 'I6-11, and having inwardly laterally extending hookportions itil-99; and extensions of the base 15 as at {0i-I0! integralwith the end iin 82' and with hook portions U19-|09 and with the hookside walls 99-99 constitute bottoms or iioors for the hook devices.

As indicated in Figs. 21 and 22, in broken line, the left end of oneunit device may be hooked into the right end of a like unit shown insolid line, to couple one unit to another longitudinally, and 'this maybe' repeated for any desired number of units to constitute a trackway ofany length for the purposes described hereinbefore.

As will be apparent,`to hook one unit to another, the hook device at theleft end of one unit is disposed above the hook device at the rightendof the other unit and then lowered into the latter.

A vehicle wheel in rolling toward the right over the two such coupledunitsA and in rolling from one to another, will not'be able by itsweight to uncouple the units because the left hand hook devices restupon the said floors IDI- IUI of the right hand hook devices.

The hook devices being of considerableA longitudinal extent at both endsof the unit, allows lateral lost motion by which, as shown in Fig. 21, asuccession of coupled units may be disposed upon a curve; and as shownin Fig. 22, a series of coupled units may follow an upward inclination;the purposes of which will be clear from the foregoing description ofother forms.

The general mode of operation of this construction of unit, and thisconstruction of coupling is the same as that described for the precedingunits hereof.

The invention is not limited to the exact constructions and embodimentsthereof illustrated and described. Changes and modifications may be madein each of them; and the invention comprehends all such changes andmodifications that may be made which come within the scope of theappended claims.

I claim:

1. In a traction device for pneumatically-tired vehicle wheels, anelongated flat base wall having opposite spaced-apart side walls; an endof the base wall being recessed to provide thereon a transverse concavearcuate edge conforming generally to theuproilleg a vehicle 4tire treadand the arcuate edselbeing `at.s'ulzstantially right 4angles to thebase; a' transverse group .gripping .the said end-1in; -this'everal finsproceedingsuc,

cessively from the 'end iin toward the otherend ofthe base Wall havingtheir concave edges successively farther from the base wall.

2. In a traction "dev-ice? forjpneumatically-tired vehicle .wheelst anelongated base wall having opposite spaced-apart side Ywallsgvan en dvofthe base wall being recessed to provide thereon a transverse concavearcuatefge'dge'..conforming generallyto the prole of a velgiicle tiretreadand the arcuate edge being 'at substantially. right angles to thebase ;"a'transverse groundlgripping calk on the undersideof thebase wallnear the recessed end a plurality 'of transverse 'longitudinally spaced"apart projecting upwardly from the )oase wall and each having anupwardly concaveedgle conforming generally to the prole of a vehicletire'tiead;"`th`e 'concave edge hof' the end n nearest the end of thebase wall being inwardly of the concave edge on the end of the basewall; the several ns, proceeding successively from the end iin towardthe other end of the base wall having their concave edges successivelyfarther from the base Wall.

3. In a traction device for pneumatically-tired vehicle wheels, anelongated base Wall having opposite spaced-apart side walls; and end ofthe base Wall being recessed to provide thereon a transverse concavearcuate edge conforming generally to the prole of a vehicle tire and thearcuate edge being at substantially right angles to the base; atransverse ground gripping calk on the underside of the base Wall nearthe recessed end; a plurality of transverse longitudinally spaced apartns, projecting upwardly from the base Wall and each having an upwardlyconcave edge conforming generally to the prole of a Vehicle tire tread;the concave edge of the end n nearest the end of the ybase Wall beinginwardly of the concave edge on the end of the base Wall.

4. In a traction device for pneumatically-tired vehicle Wheels, anelongated channel-form base; longitudinally spaced, transverse nsprojecting upwardly from the channel web, and having upwardly concaveupper edges conforming generally to the prole of a vehicle tire tread; aconcave recess in an end of the channel web conforming generally to theprole of a vehicle tire tread and the recess having an edgesubstantially at right angles to the base; the concave upper edges ofthe lns being successively farther from the channel web proceeding fromthe recessed end thereof; and a transverse calk on the underside of thechannel web near its recessed end.

5. In a traction device for pneumatically-tired vehicle wheels, anelongated channel-form base; longitudinally spaced, transverse finsprojecting upwardly from the channel web, and having upwardly concaveupper edges conforming generally to the prole of a Vehicle tire tread; aconcave recess in an end of the channel web conforming generally to thepronle of a vehicle ,tire tread and vthe recess having ari-edge'substantially at right angles to the base; and a` vtransverse callg, onthe undersideof the channel web nea-r its recessed end.

6. A traction device for pneumaticallyftired ve.'- hicle wheelscomprising, an elongated sheet inetail channel; a plurality oftransverse. elements in the channelspacedapart longitudinally of thechain- .nel; the. transverse elements having upwardly concaveedgeportlons .con forming generally to the profile of v a Vvehicle tiretread disposed suc'.- cessively farther from the. channel web; proceed-.ing from an' end thereof.; `aneud ofthe channel webhaving 'aconcaverecess therein .conforming eenerally .to the profile of a'vehiclctire tread and the recess having an edge. substantially at rightangles-to the baseia rtransverseground gripping .calkof ange-sectionmetal welded to the under channelweb having, a .concave .recess vthereinconforming generally to the profile of a vehicle' tire tread and therecess having an edge substantially at right angles to the base; atransverse ground gripping calk of iiange-section metal welded to theunderside of the web near the recessed end thereof; the said transverseelements comprising bent strips of metal welded at their ends to thechannel anges.

8. A traction device for pneumatically-tired vehicle wheels comprisingan elongated sheet metal channel; a plurality of transverse elements inthe channel spaced apart longitudinally of the channel; the transverseelements having upwardly concave edge portions conforming generally tothe prole of a vehicle tire tread disposed successively farther from thechannel web, proceeding from an end thereof; an end of the channel webhaving a concave recess therein conforming generally to the profile of avehicle tire tread and the recess having an edge substantially at rightangles to the base; a transverse ground gripping calk of Ilange-sectionmetal Welded to the under side of the web near the recessed end thereof;the said transverse elements comprising lengths of bar stock ofpolygonal section twisted about the longitudinal axis, bent into arcuateform and Welded at their ends to the channel flanges.

9. A traction device for pneumatically-tired vehicle Wheels comprisingan elongated sheet metal channel; a plurality of transverse elements inthe channel spaced apart longitudinally of the channel; the transverseelements. having upwardly concave edge portions conforming generally tothe prole of a vehicle tire tread; an end of the channel web having aconcave recess therein conforming generally to the profile of a vehicletire tread and the recess having an edge substantially at right anglesto the base; a transverse ground gripping calk of iiange-section ymetalwelded to the underside of the web near the recessed end thereof; thesaid transverse elements comprising lengths of bar stock of polygonalsection twisted about the longitudinal axis, bent into arl1 cuate formand welded at their ends to the channel flanges.

10. In a traction device for vehicle wheels, a generally rectangularunit comprising a channel form base, and a plurality of upwardly concavetransverse ns in the channel; projection means at the rectangularcorners of the unit at one end, and projection receiving means at therectangular corners at the otherrend; the projection means beingengageable .with the projection receiving means of a like unit, tocouple the two units together to form a tractionf trackway. y

1l. In a traction device for vehicle wheels, a generally rectangularunit comprising a channel form base, and a plurality lof transverseupwardly concave iins in the channel;l hooks at the rectangular cornersof the unit at one end; hook receptacles at the `rectangular .corners atthe other end; the hooks of the unit being engageable with the hookreceptacles of a like unit to couple the units together longitudinallyto form a traction trackway.

l2. In a traction device for pneumatically-tired vehicle wheels,anelongated base wall havingv opposite spaced-apart side walls; an endof the base wall being recessed to provide thereon va transverseconcave'arcuate edge conforming generally to the proiile onfY a vehicletire tread and the arcuate edge being at' substantially right angles tothe, base formed to provide aty the upper side ofthe edge a sharpcorner; a transverse ground gripping call: on the underside yof the basewall near the'recessed end; a plurality of transverse longitudinallyspaced apart fins, projecting upwardly from the base wall and eachhaving an upwardly concave edge conforming generally to the profile of avehicle tire tread; the concaveedge of the end iin nearest the end ofthe base wall being inwardly of the concave edge .on the end of the basewall and formed to provide at the side of the edge a sharp corner; theseveral fins, proceeding successively from the end fin toward the otherend ofthe base wall having theiry concave edges successively fartherfrom the basewall. l l

FRANK CESEN.

I REFERENCES CITED The following references are of record in the iile ofthis patent:

` UNITED STATES PATENTS

